Rotary impact hand tool



' May 6, 195s R. J. ASPEEK 2,833,173

VROTARY IMPACT HAND TOOL Filed Jan. 8, 1957 2/ ||I `IlZ Z L i UnitedStates .,'lih-is invention relates to fa hand tool and .more Apar;

ticularly toa self-contained hand tool. for tightening or Y looseningscrews, bolts, nuts or the` like by the translation of the impact forceof an axially movable mass into a rotational force.

v The prior art discloses a number `of axial impact screw driver orwrench-type hand tools which require the use of vtwo hands in theiroperation. That is, they must vbe) held by one hand while the other handwields a hammer, the momentum of -the mass of the head of which isappropriately translated through the impact tool into the` desiredthreading orv unthreading rotational movement.V

It is an object of the present invention to provide'a self-A containedtooll which does not derive its impact force through an auxiliary'implement such as.a-separately` wielded hammer head. Y

` ram member 12 is circular in cross-section.

2 designated-10. Thetool 10 comprises a square crosssection elongatedYshaft or stem 11. Slida'bly mounted on the vshaft or stem 11 is atubular ram -member 12. In its retracted position, as shown in Fig. 1,the ram member extends substantially above the upper end of the shaft orstem 11. Contained within the hollow portion of the ram member 12 is acompression spring 13 adapted to restore and maintain the tubular rammember in its inoperative retracted position. The spring 13 reactsbetween the upper end 14 of the stem 11 and a threaded plug 15 closingthe upper end of the chamber in the tubular ram member 12. I

The upper end of the tubular ram member 12 carries a heavy handle mass16 which may be castiron molded to substantially the elliptical contourillustrated. It is an importantfeature of the present invention that itbe understood that this handle mass 16 is a. connected or integral partof the tubular ram member 12. The'lower end of the tubular ram member-is provided with two helical lobes 17, the apexes of whichare 180"`apart. v

It will be noted that the central hole 18 of thetubular The ram memberis Vthus freely rotatable about the stem 11.- A positioning means isprovided to releasably maintain the ram member 12 in pre-selectedpositions relative to the stem 11. Referring toFignZ.. the tubular rammember In its preferred form the axial impact tool comprises anelongated stem encompassed by a tubular ram member slid-ably androtatably journalled on the upper portion of said stem. 'The tubular rammembers carries at its upper end a heavy handle mass. At its lower end,

the tubular ram member is provided with axially dependt ing helicallobes. is a tool bit adaptor having laxially extendinglob'es on theupper end thereof. The ram member lobes andthe tool bit adaptor lobesare normally in spaced axial rela- Secured to the lower end of saidsternY l v tionship to each other, the -tubular ram member being;

vrelationship to the tool bit adaptor lobes when said lobes are axiallyspaced from one another. The predetermined radial relationship .isutilized .to predetermine the direc-y tion of rotation of the tool bitadaptor upon thehandle mass being driven downwardly to cause impactengage. ment of said opposed lobes such as will'cause rotation of thetool bit adaptor. y.

Further objects and advantages and the features of construction embodiedin the present invention will be apparent from the following descriptionl.and appended claims, reference being had to the accompanying drawingyforming a part of this specification wherein like reference numeralsdesignate corresponding parts in the several views:

.Fig l` is a vsectional elevation of a ,tool fitted with an adaptor andascrew driver bit. v I

Fig. 2 is a sectionview takensubstantially through the line 2-2 in Fig.v1 looking in' the direction of the arrows. Y.

'Before explainingin vdetail thepresent invention, yit to" be understoodthat the inventionis not limited irrits application to the details ofconstruction and arrangement of parts illustrated in the accompanyingdrawing, since the invention is capable of other embodiments and ofbeing practiced or carried out in various ways.

In the drawing there is illustrated, by way of example, a preferredembodiment of the impact tool, generally 12 is provided with a pair ofdiametrically opposed pinsl 19. The pins 19 are yieldingly maintained inengagement with .the stem faces bymeans of a steel spring band orcircular clip 20 exteriorly embracing the tubular Aram member. Alsocarried on the exterior of the vtubular ram member 12 is a sleeve 21which may be slilablymoyed downwardly over the band or clip v20.yWhen-so positioned, the pins 19 are rmly held against outward movementand lock the tubular ram member 12and the st em 11 against relativerotational movement. 1 f

The lower end of the stem 11 has secured thereto a tool bit adaptor 22provided with a pair of helical ylobes237 on the upper end thereof. Thel'apexes of the lobes 23 are'also spaced 180 apart, as were the apexes ofthelob"e`s` 17 on the lower end of the tubular-ram member `12.

It will be noted that the apexes of the one set of lobes 17 aredisplaced relatively to the vapexes-'of the4 other set of lobes 23. Thisdisplacement is preferably 45circular degrees. This relativedisplacement is 'always maintained through the control that the'pins19exert on the posi- 'tionng of the tubular ram member Y12. on the shaftor stem 11. The diametrical axis of the pins -19`is so positionedrelative to the location of the apexes of the vlobes 171that the latterare always maintained at al 45"A displacement relative to the apexes ofthe lobes ,23 which are in iixed relationship to the shaft `or stem 11.yI i The l toolv bit adaptor' 22 may be'of any. conventional type adaptedtonen-rotatably hold Ya tool such as alscrew driver bitz4. `1

lImpact tools are particularly useful for sta'rting'gscrews, bolts, nutsor the like which resist turning movementby an" ordinary rtool becauseof damaged ',tlireads orbecause l they have become' frozen inposition'by corrosion; v'To dislodge-such a'screw', bolt, nut or thelike with'the iinwill be rotated in th'e proper direction. `Avs4 `showninl 1, `engagementy of ythe lobes 1.7` with .thel'lbes '231will-'resultl in thetool bit being rotated ina 'countercloc'k-f wisedirection. Should it -be desired to have the tool bit 24 rotate in aclockwise direction, it is only necessary to rotate the tubular rammember 12 ninety degrees in either direction relative to the stem 11.The spring clip` 20 will permit the pins 19 to move outwardly'a suicientdistance so that the tubular ram memberv 12 may be rothe square cornersof the stem, they` will snap back into` position so as to align thelobes 17 in proper relationship to the lobes 23. V

The tool having been set so that the tool bit `will be turned in theproper direction, the'head 25 offthe toolbit is then engaged with theobject to beloosened. The handle portion or mass 16 is then-graspedandmanually driven downwardly. The momentum ofthe vmasstiwill" betransmitted through `the tubular ram member 12 to the' adaptor 22.Because `of the helical relationship of the lobes 17 to the lobes 23, acomponent of the impact force will tendtto causethe adaptor to rotate.Inasmuch as the adaptor is rigidly secured to the end of the stem 1l,the stem `11 will also tend to 'be rotated relatively tothe tubular rammember 12. The pins 19 will permitthis since they will be drivenoutwardly against the tension of the `spring clip4 20. However, thedegree of travel caused by the helical relationship of the lobes is suchthat the relative rotation caused is less `than 90 and it will not `benecessary to reset the tool in order to repeat the impact movement. t tf The `tool embodying the present invention has'theparticular-advantag`e that the weight mass 16 is a partof the tool.Therefore, only one hand is 'needed to manipulate the tool. `Thisrisahighly desirable characteristic when the tool is `to be used underconditions where there is insutlcient room toswing a'hammer.

After `the object to be un'thre'aded has been loosened, it isIorilylnecessary to drop thesleeve 21 down over the spring clip 20thereby locking: Athe tubular ram member 12 to the stem 11 `and the toolmay then be used as a conventional device to complete the removal of thethreaded object.'

Y Iclar'nzfgfm 1. Angaxial; impact type "rotary tool comprising anelongatedetem atleast a portion of whichis of square cross``section,`atubular ram member slidably and rotatably journlledon the upperportion'of said stem, an integral heavy handlemass carriedkon theupperend Aof saidV ram-member; thelower end fof said ram member beingprovided with a 'pair of axially depending diametrically positionedhelicalflobes, a tool bit adaptorhaving a pair of axially upwardlyextending diametrically positioned helical lobes o'npthe upper endthereof, 'said' pairs of lobesgbeing normally in axiallyspacedzrelationship to each othei-jand'lpositioning means effective tomaintain `saicl ramdneniber in'a pre-selected position on said stemwhereby the apexeslof the ram: lobes are normally radially displacedononfe side or the other o f the apexes of the tool bit adaptor lobes,said radial relatio11' ship determiningthel dire'ctiorliV ofrotation: ofthe tool bit adaptorpon the handlemassfbeing driven downwardly to cause'impact engagementiof said opposed `lobesfsuch as willresult inrotationpofpthe tool bitfadaptor, said,V

positioning means comprising diametrically t opposite pins carried in`said v#ram "member ,radially engagedwith oppo-.

site faces of the stern square portion, and s prin'gmeans encirclingl'sad ram membernormally yieldingly, maintaining said pins insternengagingsipos'ition elongated stem` atleastfa portiontoflwbichis ofsquare cross-section, a tubular ram memberslidably and ,rotatf ablyjournalled on the upper portion ,of said stem, an

integralheavy handle mass carried `println; `upper end of Vpositionedhelical lobes on the upper end thereof, said pairs of lobes beingnormally in axially spaced relationadaptor upon the handle mass beingdriven downwardly to cause impact engagement of said opposed lobes suchas will result in rotation of the tool -bit` adaptor, and spring meanscontained within said ram member and compressed against the upper end ofsaid stern to retract i the same after completion of the impact stroke,said positioning means comprising diametrically opposite pins carried insaid ram member radially engaged with opposite faces of the stem squareportion, spring means encircling said ram member normally `yieldinglymaintaining said pins in stern engaging position, and a sleeveencircling said ram member and positionable over said spring means tonon-yieldingly maintain said `pins in stem engaging position.

3. An axial impact type rotary tool for turning a threaded object,comprising an elongated stern at least a portion of which is of squarecross-section,` a tubular ram member `slidably `and rotatably journalledon the uppervp'orti'on of said stem, an integralheavy handle masscarried on the upper end ofsaid ram member, the lower `V end of said rammember being provided with a pair of axially depending diametricallypositionedhelical lobes, a tool lbit adaptor'having a pair of axiallyupwardly extending diametrically positioned helical lobes on the upperend thereof, said pairs of lobes being normally in axially spacedrelationship to each other, positioning means effective to maintain saidram member in a pre-selected position on said stem whereby theapexes ofthe ram lobes are normally radially displaced approximately 45 on oneside or the other of the apexes of the tool ybit adaptor lobes, 'saidradial relationship determining the direction of rotation of the toolbit adaptor `upon the handle mass being driven downwardly to causeimpact engagement of said opposed lobes such as will result in rotationVof the tool bit adaptor, spring means contained within said ram memberand compressed against the upper end of said stem to retract the sameafter completion of the impact stroke, and sleeve means positionable toblock such movementof said pin means as would permit relative rotationalmovement of the ram member about Said stern, said positioning meanscomprising diametricallyu opposite pins carried in said ram memberradially engaged with opposite faces of the stemsquare portion, springmeans encircling said ram member normally yieldingly maintaining saidpins in stem engaging position,`

and a sleeve encircling said ram member and positionable over saidspring means to non-,yieldingly maintainA saidpins in stem engagingposition.

2,010,616 Walsh Aug. 6, 1935 2,631,484 Spielman Mar. 17, 1953 2,633,042Halverson Mar. 31 1953 2,635,497 Spielman Apr. 2l, 1953 2,638,806Spielman May 19, 1953 FOREIGN PATENTS 61,912 France Dec. 15, 1954710,707 Great `Britain June 16, 1954 .1,009,278

Prancev- Mar. 5, 1952

